This book provides historical background on the enactment of declarations of war and authorisations for the use of force and analyses their legal effects under international and domestic law. It also sets forth their texts in two appendices. Because the statutes that confer standby authority on the President and the executive branch potentially play such a large role in an armed conflict to which the United States is a party, the book includes an extensive listing and summary of the statutes that are triggered by a declaration of war, a declaration of national emergency, and/or the existence of a state of war. The book concludes with a summary of the congressional procedures applicable to the enactment of a declaration of war or authorisation for the use of force and to measures under the War Powers Resolution.